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1 /*
2  * Copyright (C) 2014 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #define LOG_TAG "alsa_device_proxy"
18 /*#define LOG_NDEBUG 0*/
19 /*#define LOG_PCM_PARAMS 0*/
20 
21 #include <log/log.h>
22 
23 #include <errno.h>
24 
25 #include "include/alsa_device_proxy.h"
26 
27 #include "include/alsa_logging.h"
28 
29 #define DEFAULT_PERIOD_SIZE     1024
30 #define DEFAULT_PERIOD_COUNT    2
31 
32 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
33 
34 static const unsigned format_byte_size_map[] = {
35     2, /* PCM_FORMAT_S16_LE */
36     4, /* PCM_FORMAT_S32_LE */
37     1, /* PCM_FORMAT_S8 */
38     4, /* PCM_FORMAT_S24_LE */
39     3, /* PCM_FORMAT_S24_3LE */
40 };
41 
proxy_prepare(alsa_device_proxy * proxy,alsa_device_profile * profile,struct pcm_config * config)42 void proxy_prepare(alsa_device_proxy * proxy, alsa_device_profile* profile,
43                    struct pcm_config * config)
44 {
45     ALOGV("proxy_prepare(c:%d, d:%d)", profile->card, profile->device);
46 
47     proxy->profile = profile;
48 
49 #ifdef LOG_PCM_PARAMS
50     log_pcm_config(config, "proxy_setup()");
51 #endif
52 
53     if (config->format != PCM_FORMAT_INVALID && profile_is_format_valid(profile, config->format)) {
54         proxy->alsa_config.format = config->format;
55     } else {
56         ALOGW("Invalid format %d - using default %d.",
57               config->format, profile->default_config.format);
58         proxy->alsa_config.format = profile->default_config.format;
59     }
60 
61     if (config->rate != 0 && profile_is_sample_rate_valid(profile, config->rate)) {
62         proxy->alsa_config.rate = config->rate;
63     } else {
64         ALOGW("Invalid sample rate %u - using default %u.",
65               config->rate, profile->default_config.rate);
66         proxy->alsa_config.rate = profile->default_config.rate;
67     }
68 
69     if (config->channels != 0 && profile_is_channel_count_valid(profile, config->channels)) {
70         proxy->alsa_config.channels = config->channels;
71     } else {
72         proxy->alsa_config.channels = profile_get_closest_channel_count(profile, config->channels);
73         ALOGW("Invalid channel count %u - using closest %u.",
74               config->channels, proxy->alsa_config.channels);
75     }
76 
77     proxy->alsa_config.period_count = profile->default_config.period_count;
78     proxy->alsa_config.period_size =
79             profile_get_period_size(proxy->profile, proxy->alsa_config.rate);
80 
81     // Hack for USB accessory audio.
82     // Here we set the correct value for period_count if tinyalsa fails to get it from the
83     // f_audio_source driver.
84     if (proxy->alsa_config.period_count == 0) {
85         proxy->alsa_config.period_count = 4;
86     }
87 
88     proxy->pcm = NULL;
89     // config format should be checked earlier against profile.
90     if (config->format >= 0 && (size_t)config->format < ARRAY_SIZE(format_byte_size_map)) {
91         proxy->frame_size = format_byte_size_map[config->format] * proxy->alsa_config.channels;
92     } else {
93         proxy->frame_size = 1;
94     }
95 }
96 
proxy_open(alsa_device_proxy * proxy)97 int proxy_open(alsa_device_proxy * proxy)
98 {
99     alsa_device_profile* profile = proxy->profile;
100     ALOGV("proxy_open(card:%d device:%d %s)", profile->card, profile->device,
101           profile->direction == PCM_OUT ? "PCM_OUT" : "PCM_IN");
102 
103     if (profile->card < 0 || profile->device < 0) {
104         return -EINVAL;
105     }
106 
107     proxy->pcm = pcm_open(profile->card, profile->device,
108             profile->direction | PCM_MONOTONIC, &proxy->alsa_config);
109     if (proxy->pcm == NULL) {
110         return -ENOMEM;
111     }
112 
113     if (!pcm_is_ready(proxy->pcm)) {
114         ALOGE("  proxy_open() pcm_open() failed: %s", pcm_get_error(proxy->pcm));
115 #if defined(LOG_PCM_PARAMS)
116         log_pcm_config(&proxy->alsa_config, "config");
117 #endif
118         pcm_close(proxy->pcm);
119         proxy->pcm = NULL;
120         return -ENOMEM;
121     }
122 
123     return 0;
124 }
125 
proxy_close(alsa_device_proxy * proxy)126 void proxy_close(alsa_device_proxy * proxy)
127 {
128     ALOGV("proxy_close() [pcm:%p]", proxy->pcm);
129 
130     if (proxy->pcm != NULL) {
131         pcm_close(proxy->pcm);
132         proxy->pcm = NULL;
133     }
134 }
135 
136 /*
137  * Sample Rate
138  */
proxy_get_sample_rate(const alsa_device_proxy * proxy)139 unsigned proxy_get_sample_rate(const alsa_device_proxy * proxy)
140 {
141     return proxy->alsa_config.rate;
142 }
143 
144 /*
145  * Format
146  */
proxy_get_format(const alsa_device_proxy * proxy)147 enum pcm_format proxy_get_format(const alsa_device_proxy * proxy)
148 {
149     return proxy->alsa_config.format;
150 }
151 
152 /*
153  * Channel Count
154  */
proxy_get_channel_count(const alsa_device_proxy * proxy)155 unsigned proxy_get_channel_count(const alsa_device_proxy * proxy)
156 {
157     return proxy->alsa_config.channels;
158 }
159 
160 /*
161  * Other
162  */
proxy_get_period_size(const alsa_device_proxy * proxy)163 unsigned int proxy_get_period_size(const alsa_device_proxy * proxy)
164 {
165     return proxy->alsa_config.period_size;
166 }
167 
proxy_get_period_count(const alsa_device_proxy * proxy)168 unsigned int proxy_get_period_count(const alsa_device_proxy * proxy)
169 {
170     return proxy->alsa_config.period_count;
171 }
172 
proxy_get_latency(const alsa_device_proxy * proxy)173 unsigned proxy_get_latency(const alsa_device_proxy * proxy)
174 {
175     return (proxy_get_period_size(proxy) * proxy_get_period_count(proxy) * 1000)
176                / proxy_get_sample_rate(proxy);
177 }
178 
proxy_get_presentation_position(const alsa_device_proxy * proxy,uint64_t * frames,struct timespec * timestamp)179 int proxy_get_presentation_position(const alsa_device_proxy * proxy,
180         uint64_t *frames, struct timespec *timestamp)
181 {
182     int ret = -EPERM; // -1
183     unsigned int avail;
184     if (proxy->pcm != NULL
185             && pcm_get_htimestamp(proxy->pcm, &avail, timestamp) == 0) {
186         const size_t kernel_buffer_size =
187                 proxy->alsa_config.period_size * proxy->alsa_config.period_count;
188         if (avail > kernel_buffer_size) {
189             ALOGE("available frames(%u) > buffer size(%zu)", avail, kernel_buffer_size);
190         } else {
191             int64_t signed_frames = proxy->transferred - kernel_buffer_size + avail;
192             // It is possible to compensate for additional driver and device delay
193             // by changing signed_frames.  Example:
194             // signed_frames -= 20 /* ms */ * proxy->alsa_config.rate / 1000;
195             if (signed_frames >= 0) {
196                 *frames = signed_frames;
197                 ret = 0;
198             }
199         }
200     }
201     return ret;
202 }
203 
204 /*
205  * I/O
206  */
proxy_write(alsa_device_proxy * proxy,const void * data,unsigned int count)207 int proxy_write(alsa_device_proxy * proxy, const void *data, unsigned int count)
208 {
209     int ret = pcm_write(proxy->pcm, data, count);
210     if (ret == 0) {
211         proxy->transferred += count / proxy->frame_size;
212     }
213     return ret;
214 }
215 
proxy_read(const alsa_device_proxy * proxy,void * data,unsigned int count)216 int proxy_read(const alsa_device_proxy * proxy, void *data, unsigned int count)
217 {
218     return pcm_read(proxy->pcm, data, count);
219 }
220 
221 /*
222  * Debugging
223  */
proxy_dump(const alsa_device_proxy * proxy,int fd)224 void proxy_dump(const alsa_device_proxy* proxy, int fd)
225 {
226     if (proxy != NULL) {
227         dprintf(fd, "  channels: %d\n", proxy->alsa_config.channels);
228         dprintf(fd, "  rate: %d\n", proxy->alsa_config.rate);
229         dprintf(fd, "  period_size: %d\n", proxy->alsa_config.period_size);
230         dprintf(fd, "  period_count: %d\n", proxy->alsa_config.period_count);
231         dprintf(fd, "  format: %d\n", proxy->alsa_config.format);
232     }
233 }
234